Proper Motions and Orbits of Distant Local Group Dwarf Galaxies from a Combination of Gaia and Hubble Data

被引：8

作者：

Bennet, Paul ^{[1
]}

Patel, Ekta ^{[2
,3
]}

Sohn, Sangmo Tony ^{[1
]}

Molina, Andres del Pino ^{[4
]}

van der Marel, Roeland P. ^{[1
,5
]}

Libralato, Mattia ^{[6
]}

Watkins, Laura L. ^{[6
]}

Aparicio, Antonio ^{[7
,8
]}

Besla, Gurtina ^{[9
]}

Gallart, Carme ^{[7
,8
]}

Fardal, Mark A. ^{[10
]}

Monelli, Matteo ^{[7
,8
,11
]}

Sacchi, Elena ^{[12
]}

Tollerud, Erik ^{[1
]}

Weisz, Daniel R. ^{[2
]}

机构：

[1] Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA

[2] Univ Calif Berkeley, Dept Astron, 501 Campbell Hall, Berkeley, CA 94720 USA

[3] Univ Utah, Dept Phys & Astron, 115 South 1400 East, Salt Lake City, UT 84112 USA

[4] CSIC, Ctr Estudios Fis Cosmos Aragon CEFCA, Unidad Asociada, Plaza San Juan 1, Teruel 44001, Spain

[5] Johns Hopkins Univ, Ctr Astrophys Sci, William H Miller III Department Phys & Astron, Baltimore, MD 21218 USA

[6] European Space Agcy ESA, AURA, ESA Off, Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA

[7] Intituto Astrofis Canarias, Tenerife 3200, Canary Islands, Spain

[8] Univ La Laguna, Dept Astrofis, Tenerife 3200, Canary Islands, Spain

[9] Univ Arizona, Dept Pediat, Tucson, AZ 85721 USA

[10] Eureka Sci, 2452 Delmer St,Suite 100, Oakland, CA 61530 USA

[11] INAF Osservatorio Astron Roma, Via Frascati 33, I-00040 Monte Porzio Catone, Italy

[12] Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany

来源：

ASTROPHYSICAL JOURNAL | 2024年 / 971卷 / 01期

关键词：

STAR-FORMATION HISTORIES; SATELLITE LUMINOSITY FUNCTION; LARGE-MAGELLANIC-CLOUD; MILKY-WAY; COSMOLOGICAL SIMULATIONS; M31-LIKE GALAXIES; GAS CONTENT; LEO I; MASS; II;

D O I：

10.3847/1538-4357/ad5349

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We have determined the proper motions (PMs) of 12 dwarf galaxies in the Local Group (LG), ranging from the outer Milky Way (MW) halo to the edge of the LG. We used the Hubble Space Telescope (HST) as the first and Gaia as the second epoch using the GaiaHub software. For Leo A and Sag DIG, we also used multi-epoch HST measurements relative to background galaxies. Orbital histories derived using these PMs show that two-thirds of the galaxies in our sample are on first infall with >90% certainty. The observed star formation histories of these first-infall dwarfs are generally consistent with infalling dwarfs in simulations. The remaining four galaxies have crossed the virial radius of either the MW or M31. When we compare their star formation (SF) and orbital histories we find tentative agreement between the inferred pattern of SF with the timing of dynamical events in the orbital histories. For Leo I, SF activity rises as the dwarf crosses the MW's virial radius, culminating in a burst of SF shortly before pericenter (approximate to 1.7 Gyr ago). The SF then declines after pericenter, but with some smaller bursts before its recent quenching (approximate to 0.3 Gyr ago). This shows that even small dwarfs like Leo I can hold onto gas reservoirs and avoid quenching for several gigayears after falling into their host, which is longer than generally found in simulations. Leo II, NGC 6822, and IC 10 are also qualitatively consistent with this SF pattern in relation to their orbit, but more tentatively due to larger uncertainties.

引用

页数：23